Due to an early exit from the UEFA Champions League 2003–04 and coupled with the arrival of new coach Fabio Capello, Juventus began a restructuring of their first team squad.

In his second season, Di Vaio became the third choice striker behind new signings Jan Koller and Jérémy Menez, restricting him to just six first team appearances.

On 22 January 2007, after an unsuccessful spell in Ligue 1, Di Vaio surprisingly returned to Italy by signing with Serie B club Genoa,[14] a side strongly pushing for promotion, for €1.8 million.

[15] The club duly achieved promotion, but once in Serie A, the partnership of Marco Borriello and Giuseppe Sculli was preferred, leaving Di Vaio to make only nine appearances.

[15] In his period at Bologna, Di Vaio regained reputation as a key prolific striker, rapidly becoming a fan favourite, as well as team captain and one of the reference players during the two club takeovers in the 2010–11 season, ensuring himself a contract extension until June 2013; following the announcement, Di Vaio also state his desire to spend the rest of his footballing career as a Bologna player.

[18] After lengthy negotiations, Montreal Impact announced that Marco Di Vaio had signed as the Canadian club's first Designated Player.

[19] Di Vaio made his Impact debut on 27 June 2012 against Toronto FC, and scored his first goal a month later on 28 July 2012 against New York Red Bulls.

He scored his first goal for Italy on 11 October 2003, in Reggio Calabria, in a 4–0 home win over Azerbaijan in a UEFA Euro 2004 qualifying match.

However, a loss of form whilst with Valencia, coupled with the emergence of Luca Toni and Alberto Gilardino, led to Di Vaio losing his place with the national team.

[24] A prolific goalscorer, Di Vaio was a quick, opportunistic, and versatile player, who was capable of playing anywhere along the front-line, as a striker, or even as a winger, due to his solid technique and distribution.